回首已陌路
[huí shŏu yĭ mò lù]
'回首已陌路' translates to 'Turn Back and the Road is Unfamiliar,' which describes a poignant sense of nostalgia mixed with a feeling of estrangement when revisiting past experiences or people. It signifies someone who reflects on former relationships or times but feels those experiences have changed, creating unfamiliarity and perhaps sadness at what once was close becoming so distant.